Preheat oven to 225°F and line a baking sheet with parchment paper, set it to the side for now.
Use an apple corer to remove the core from 4 small sweet apples.
Use a mandoline to make ⅛” thick slices perpendicular to the direction of the core. A hole should be at the center of each slice, thus making apple rings! The yield is usually around 60 slices.
Lay the slices in a single layer on the prepared baking sheet. Their edges can touch because they will shrink while in the oven. Just make sure they aren't overlapped.
Sprinkle cinnamon on top of the slices, if desired.
Bake the apple slices in the oven at 225°F for 90 minutes.
Remove the baking sheet from the oven and flip the slices over. Return to the oven and bake for an additional 30 minutes.
Remove from the oven and let them rest on the hot baking sheet for 5 to 10 minutes. The chips will be slightly soft at first but will continue to crisp up.
Notes
Apple Slicing Notes: I set my mandoline to the second from the thinnest setting to get the apple slices to be ⅛” thick. The thinnest setting was almost paper thin, and the apple would not have held up well in the oven. Thicker than ⅛”, the apple chips would be chewy or take a lot longer to dry out.Use a food holder or food guard as you near the end of each apple to protect your fingers. If you're confident with your knife skills, you can chop your apples by hand.Storage: Allow your baked apple chips to cool completely before storing them. Then, lay them in an airtight container or resealable plastic bag at room temperature. Homemade apple chips will last several days but are best when eaten immediately.